Southwest of St. Louis, the Chubb Trail is a locally favored 7 mile mountain biking route with rocky terrain and nasty dropoffs. Its marked as 7 miles long beginning with a very challenging 3 miles through the wooded hillside with some challenging roots, rocks, and gravelly climbs with all of the above. You are progressing (generally) down to the Merramec (sp?) River for about 2 miles of easy winding riverside trail before a mile of gravel road ending in a long and moderately steep climb to Lone Elk Park (where you either hop into a friends vehicle or suck it up for the mountain bike ride back!). NOTE: VERY treacherous when the trail is wet (rock and roots become very slick).
To reach the mountain biking trailhead from St. Louis, follow US44 west to exit #265 (Lewis Road). Pass into Tyson Park and proceed to the end of the road.
Overall, West Tyson County Park is the 13th most popular mountain bike trail of all 27 mountain biking rides in Missouri.